1. Field of the Invention
The present invention relates to a clean box constructed in structure that objects to be transferred, necessary for production processes of semiconductors, electron-device-associated products, optical disks, etc., can be transferred in a clean state containing no contaminants and, particularly, in such structure that the objects to be transferred can carried into or out of the box through a side aperture thereof, and also relates to a clean transfer method and apparatus suitably applicable for transferring this clean box by an OHT (overhead transfer) or the like and connecting the clean box to a clean device.
2. Related Background Art
The inventor of the present invention suggested the clean box of a side open type in Japanese Laid-open Patent Application No. 10-321696 laid open on Dec. 4, 1998) which was also assigned to the assignee of the present invention. Use of this clean box of the side open type presents the following advantage; the objects to be transferred can be carried in and out of the box through the side aperture and waste vertical motion of the objects to be transferred can be eliminated.
There is a local clean space system for fabrication of semiconductors now under study toward use, which is used as follows; a load port mechanism 1 as illustrated in FIG. 9 is attached to an entrance/exit part of each clean device used in carrying semiconductor wafers into or out of the device, the side open type clean box 10 of a mechanical seal method as illustrated in FIG. 10 is mounted on a load port table 2 of the load port mechanism 1, the table 2 is moved by about 30 mm toward a gate aperture 3 of the load port mechanism 1 to connect an opening/closing lid 12 of the clean box 10 to a gate valve 4 closing the gate aperture 3, mechanical latches of the opening/closing lid 12 are released, and the opening/closing lid 12 and the gate valve 4 are opened simultaneously.
As illustrated in FIG. 10, the clean box 10 is composed of a box body 11 and the opening/closing lid 12, and is provided with latches 15, each being composed of a pair of lock pins 13 and a piece 14 having a key groove 14a and located in the middle, in order to keep the opening/closing lid 12 from being dismounted from the box body 11. Normally, the lock pins 13 are fitted in corresponding holes 16 formed in inside surfaces of the box body 11, so as to make the latches 15 active. When the clean box 10 is connected to the gate valve 4 of the load port mechanism 1, latch keys 5 on the gate valve side come to engage the associated key grooves 14a formed in the pieces 14. Then the latch keys 5 are rotated to release the latches of the opening/closing lid 12.
Incidentally, in the system illustrated in FIG. 9 and FIG. 10, the mechanism for opening or closing the opening/closing lid 12 of the clean box 10 needs to be set on the gate valve 4 side; i.e., the driving section for opening/closing is located in the clean space, which would be the cause of dust.
In cases where the clean box is held and transferred by the OHT installed on a ceiling surface of a plant, there arises another problem that it is very difficult to fit the clean box lowered by the OHT from above into positioning pins on the load port table of the load port mechanism.
A first object of the present invention is, in view of the above points, to provide a clean box having such structure that latches engaging the outside surface of the opening/closing lid of the clean box can be released from the non-clean space side beside the clean box, so as to prevent production of dust during latching/unlatching of the latches, and also provide a clean transfer method and apparatus using the clean box.
A second object of the present invention is to provide a clean transfer method and apparatus in a configuration suitable for application in which the clean box is moved up and down by the OHT or the like to be connected to a clean device.
The other objects and novel features of the present invention will become apparent in the description of embodiment hereinafter.
In order to accomplish the above objects, a clean box of the present invention is a clean box comprising a box body having an aperture in one side surface; an opening/closing lid for hermetically closing said aperture while undergoing vacuum suction to the box body; and a plurality of latches provided on said box body so as to be able to engage the opening/closing lid outside said box body.
In the clean box, it is desirable that said latches be able to be unlatched from outer and lateral sides of said box body, which are side positions with respect to the side surface having said aperture.
The clean box may have such a configuration that said box body has an annular groove for suction surrounding said aperture in said one side surface and also has an intake/exhaust port in communication with said annular groove for suction in another surface.
The box body may comprise a gas inlet valve and a gas outlet valve.
A clean transfer method of the present invention is a clean transfer method comprising steps of:
preparing a clean box comprising a box body having an aperture in one side surface, an opening/closing lid for hermetically closing said aperture while undergoing vacuum suction to the box body, and a plurality of latches provided on said box body so as to be able to engage the opening/closing lid outside said box body;
preparing a clean device in which a gate aperture formed in a side wall surface is hermetically closed by a gate valve, said clean device comprising box up-and-down guides and latch releasing means on the both sides of said gate aperture outside the side wall surface and further comprising a moving table below said gate aperture and outside said side wall surface;
mounting said clean box on said moving table by lowering said clean box while guiding the clean box by said box up-and-down guides; and
hermetically connecting said clean box to said gate aperture by movement of said moving table, thereafter unlatching said latches by said latch releasing means, releasing the vacuum suction of said opening/closing lid to said box body, drawing said opening/closing lid, together with said gate valve, into said clean device to establish communication between an inside space of said clean box and the inside of said clean device, and transferring objects to be transferred between said clean box and said clean device.
A clean transfer apparatus of the present invention is a clean transfer apparatus comprising:
a clean box comprising a box body having an aperture in one side surface, an opening/closing lid for hermetically closing said aperture while undergoing vacuum suction to the box body, and a plurality of latches provided on said box body so as to be able to engage the opening/closing lid outside said box body; and
a clean device comprising a gate aperture formed in a side wall surface, a gate valve capable of opening or closing the gate aperture and holding the opening/closing lid of the clean box connected to the gate aperture, box up-and-down guides and latch releasing means provided on the both sides of said gate aperture outside said side wall surface, and a moving table provided below said gate aperture and outside said side wall surface,
wherein said box up-and-down guides are guides for guiding said clean box while said clean box is lowered onto said moving table or while said clean box is moved up away from said moving table, and the latch releasing means are means for unlatching said latches from outer and lateral sides of said box body, and
wherein in a state in which said clean box is connected to said gate aperture, said latches are unlatched by said latch releasing means, the vacuum suction of said opening/closing lid to said box body is released, and said opening/closing lid, together with said gate valve, is drawn into said clean device to establish communication between an inside space of said clean box and the inside of said clean device.
In the clean transfer apparatus, the box up-and-down guides also serve as covers for covering the latch releasing means in a preferred configuration.
Since the clean box of the present invention is arranged to have the box body having the aperture in one side surface, the opening/closing lid for hermetically closing the aperture while undergoing the vacuum suction to the box body, and the plurality of latches provided on the box body so as to be able to engage the opening/closing lid outside the box body, the clean box has the following advantages; adhesion of the opening/closing lid is firmer than in the conventional simple mechanical seal; the objects to be transferred can be transferred or stored in a sealed state with a clean gas; prevention of a drop of the opening/closing lid is implemented by the compact mechanism; handling of the box is easy.
In the clean transfer method and apparatus of the present invention, the latches on the clean box side can be unlatched from the outside of the clean space, whereby dust and fine particles are prevented from contaminating the clean space with latching/unlatching of the latches. Further, the box up-and-down guides are provided on the both sides of the gate aperture to which the clean box is connected, so that the clean box can be positioned and mounted on the moving table by lowering the clean box while guiding it by the box up-and-down guides.
The clean box according to the present invention has neither evacuation means itself, such as a pump for evacuating the inside of the box, nor transfer means for transferring the box.